East Palo Alto Planning: ADU Analysis

The following map shows all buildable area for attached and detached ADUs in East Palo Alto.

• Hover over parcels to see addresses. Existing buildings and buildable area are only mapped for residential parcels.
• Hover over existing buildings to see the existing gross building sqft.
• The green region is detached ADU buildable area. It’s 4ft from side/rear, 6ft from existing buildings, no closer to the street than the existing building, and can fit at least an 8ft x 20ft structure. Hover over the green area to see the maximum detached ADU that can be built on the green area of the parcel. This is capped at 1,200 sqft per state regulations, even if the green space is much larger.
• The yellow region (including green) is attached ADU buildable area. It doesn’t have the 6ft setback from existing buildings. Hover over the yellow area to see the maximum attached ADU that can be built on the parcel. This is capped at 50% of existing gross building sqft or 1,200 sqft.
• This Drive folder has the raw data (including owner names and many Assessor building characteristics) in CSV form, as well as shapefile versions based on parcel geometry, building geometry, and attached/detached buildable area geometries.
• More information about the methodology and data sources will be prepared in an Appendix soon.

load("epa_parcels_adus.Rdata")

epa_parcels_adus_map

# include_url("https://city.systems/epa-adu/epa_parcels_adus_map.html")

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Next are some summary statistics.

First, here’s the breakdown of parcels by residential zoning type in General Plan 2035. The parcel shapes and zoning were pulled from ArcGISOnline. Note there were some inconsistencies in APN designation between this zoning file and the County’s Assessor record. 6 residential parcels were manually re-coded from Assessor APN to EPA General Plan APN.

New state regs require ADUs to be allowed in all residentially zoned parcels.

Of residentially zoned parcels, below is the breakdown of property use code according to the County Assessor, which should represent as of early 2019 the existing use. The table also notes which PUCs we considered to be “ADU eligible” for our analysis, and completed the buildable area analysis for. Note the following key caveats:

• If a residentially zoned lot is currently vacant (PUC: 0), buildable area analysis wasn’t performed. But if the property owner were to build a residential building, then it’s likely they would also subsequently be able to build an ADU. So our ADU numbers will be underestimates because they don’t include currently vacant residential lots.
• Larger multifamily buildings (5+ units) are not included in the buildable area analysis, although they are technically ADU eligible. Such buildings are typically very differently designed than low-density housing, and have their own special state ADU regulations. We would assume that most of the ADU opportunities for such buildings are internal ADU conversions.

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# hist(epa_parcels_adus$max_detached_buildable_area, breaks=c(seq(0,1200,50)),xlim = c(0,1200))

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# hist(epa_parcels_adus$max_attached_buildable_area, breaks=c(seq(0,1200,50)),xlim = c(0,1200))

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More summary statistics coming soon.